For every zone of your plume, we’ve got you covered!

Leaders in Remediation of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS)

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- Enhances Efficiency

- Minimizes Methane Production

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Electron Donor

Solutions for


Reductive Dechlorination

Formulating Surfactant Blends

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Additive injection and groundwater recirculation trailers available for short or long term lease.

TersOx™ - Inorganic Peroxygen for Enhanced Aerobic Bioremediation

RemBind designed to treat TPH, PAH, PFOS, PCBs, PCPs, and various pesticides

Sulfate Enhanced Bioremediation 

Our Team

Technical Support


emailGary M. Birk, P.E.
Managing Partner at Tersus Environmental

Gary Birk is the founder and Managing Partner for Tersus Environmental.  He has a bachelor’s degree in chemical engineering from North Carolina State University and holds registrations as a Professional Engineer in North Carolina, Virginia and Florida.   Well-known for his contributions to in situ anaerobic groundwater remediation, he has worked on over 200 enhanced reductive dechlorination projects in North America, Europe, Asia and Africa.

His focus is on engaging cutting-edge sustainable green technologies that help environmental consulting companies restore or remediate groundwater and soil at challenging sites associated with Fortune 500 companies, the U.S. Departments of Energy and Defense, and NASA.  Gary has worked extensively in the field of bioremediation and environmental consulting on soil and groundwater assessments and cleanups.  His experience includes two decades as an environmental contractor and consultant focused on project management of multiphase, multidisciplinary environmental design and construction projects, predominantly for industry and utilities.  Gary has authored Design Tools for in situ bioremediation that have advanced the state-of-the-practice in estimating substrate application rates.  Gary’s current focus is on remediation of emerging contaminants such as Per- and Polyfluoroalkyl Substances (PFAS).


emailAaron Archibald
Partner at Tersus Environmental

As a partner, Aaron is key member of the Tersus Team. He takes an active role in the overall management of the company, its strategic thrust and efforts to commercialize our corporate developed technologies. Aaron brings 20 years of sales, marketing and management experience having worked both in the international financial and remediation sectors. This experience is key to his involvement in reviewing and approving large contracts, developing intellectual property and the transfer and licensing of technologies. As part of his management duties Aaron works closely with our US sales team.

Aaron oversees strategic partnerships while coordinating between our regional account managers and technical experts to ensure the development and delivery of appropriate action plans and solutions to clients. Coordinating human resources, technology selection, cost efficiencies, action plans and managing time tables is key to our delivery of solutions to our clients that meet scheduling, cost and technical needs.

John Archibald

emailJohn Archibald, P.Eng.
Partner / PFAS Practice Leader

As a professional engineer, John brings 30 years of management and international experience having worked both in North America and overseas. For a number of years in his position as a senior vice president with a large American conglomerate, he effectively and aggressively managed large business units and led their productive growth and profitability.  His experience includes start up situations and opening overseas offices and manufacturing facilities.  John has worked with numerous small technology firms launching their initiatives into the marketplace and has been regularly involved in the transfer and licensing of technologies as part of his activities. 

John is an engineering graduate of the University of Waterloo and is a practicing professional engineer. 

DAlden Pic - Copy 2

emailDavid F. Alden, P.E.
Technical Associate

David Alden is a Technical Associate with Tersus Environmental where he provides technical support for Tersus’ portfolio of biotechnology-based solutions to manage complex, challenging environmental liabilities and reduce costs for site closure. He is a graduate of Universidad de las Americas-Puebla, Mexico, where he majored in Civil Engineering with a focus on waste-water treatment and and holds registration as a Professional Engineer in North Carolina. Alden worked for 4 years in the upstream oilfield sector performing offshore well tests and completion design and installation in the Gulf of Mexico. He participated in the in-situ oil-shale extraction experiment in the Piceance Basin, in Northwestern Colorado where protecting groundwater was the main challenge. Alden recently specialized in groundwater studies, completing a Masters Degree program in Joseph Fourier University, Grenoble France.

David is a member of the Interstate Technology and Regulatory Council (ITRC), a public-private coalition working to reduce barriers to the use of innovative environmental technologies that reduce compliance costs and maximize cleanup efficacy. He is currently an active member of ITRC’s Remediation Management of Complex Sites Team and is the recipient of the 2015 ITRC Industry Affiliates Program Award in recognition of his outstanding service.


emailMark E. Selman, P.E.
Technical Sales Representative

Mark has a bachelor's degree in Environmental Resource Management and a Masters in Environmental Pollution Control from the Pennsylvania State University.  He holds registrations as a Professional Engineer in Colorado, Wyoming, Oregon, and Washington.  Mark has a wealth of experience within the industry, having spent the last 30 years as an environmental engineer providing regulatory compliance, site investigation, and remedial consulting services.  As a Technical Sales Representative, Mark provides technical support to help clients evaluate the feasibility of using Tersus' proven portfolio of products and technologies to reduce uncertainty, minimize risks, and achieve cost-effective results.

 Scientific Advisory Team - Surfactants

Harwell portrait 1  Jeffrey H. Harwell, Ph.D.
Asahi Glass Chair Professor - School of Chemical Engineering & Materials Science, University of Oklahoma
Fellow - The American Institute of Chemical Engineers
Cofounder and Principal - Surbec

Dr. Harwell is a Surbec Principal and has been on the faculty of Chemical Engineering at the University of Oklahoma for over 25 years. Almost all of Dr. Harwell's research concerns surfactants and colloid science; much of it is directly related to applications. His research ranges from applied areas such as environmental remediation (in situ ground water remediation) or polymer composites (modification fillers and reinforcers by admicellar polymerization), to basic areas such as microemulsion theory and surfactant precipitation, which support the large number of industries that utilize surfactants. Applications of his research range from remediation of groundwater contaminated by fuels or solvents, to novel materials for new tire treads, to improved cleaning formulations. All of these topics are connected through the importance of surfactants in controlling interfacial properties in engineering systems. Dr. Harwell has edited four books, Surfactant Based Separations Processes (1989), Surfactant-Enhanced Subsurface Remediation: Emerging Technologies (1995), Surfactant-Based Separations: Science and Technology (2000) and Reuse of Surfactants and Cosolvents for NAPL Remediations (1999). He also has published more than 150 refereed papers and published presentations and is an inventor on sixteen issued patents.


Bor-Jier (Benjamin) Shiau, Ph.D., P.E.
Director of Surfactant Technology - Surbec

Dr. Shiau has over ten years research experience in designing groundwater remediation systems. He has designed surfactant systems for several field demonstrations of surfactant enhanced subsurface remediation (SESR) at DOD sites (Hill AFB, NAVY Alameda Point, McClellan AFB, Tinker AFB), and countless industrial or UST sites throughout the U.S. His experince also includes the develoment of innovative permeable reactive barrier (PRB) system for treating inorganic contaminants such as nitrate and Cr(VI) for the U.S. EPA, Robert S. Kerr Environmental Research Center, Ada, OK. Dr Shiau has served as a Reviewer for: Environmental Science and Technology, Journal of Environmental Engineering (ASCE), Ground Water, Langmuir, Water Research, Waste Management, Environmental Research Brief (USEPA).


Mark A. Hasegawa, P.E., MS
Principal - Hasegawa Engineering

Mark Hasegawa is a Principal with Hasegawa Engineering. He has a bachelor's degree in civil engineering from Brigham Young University and a masters in civil engineering for University of Oklahoma. Mark is one of the primary contributors to ITRC’s Technical and Regulatory Guidance for Surfactant/Cosolvent Flushing of DNAPL Source Zones.

Scientific Adviser - Sorption and Chemical Immobilization (RemBind™)

 richard stewart Richard J. Stewart, Ph.D.
Managing Director | Ziltek Pty Ltd.

Scientific Adviser - Bioremediation


Kevin T. Finneran, Ph.D.
Associate Professor
Kavli Fellow, National Academy of Sciences (NAS)
Department of Environmental Engineering and Earth Sciences, Clemson University

Dr. Kevin T. Finneran is an associate professor of environmental engineering at Clemson University in the department of Environmental Engineering and Earth Sciences.  He is internationally recognized as an expert on bioremediation and biodegradation, contaminated site remediation, and microbial physiology related to the metabolism of recalcitrant compounds.  He has also been an independent consultant for contaminated site remediation projects for several private clients since 2008.  He has a Ph.D. in Microbiology from the University of Massachusetts at Amherst (2001), and a B.S. in Environmental Sciences from Rutgers University (1996).  Prior to Clemson, he was an Assistant Professor at University of Illinois Urbana-Champaign, and a consultant at Geosyntec Consultants in Acton, MA. 

His research and consulting work focus on contaminated site remediation, with emphases on novel tools and technologies for site cleanup and combined strategies for faster and more sustainable remediation.  His research group’s primary expertise is mixed biological and chemical reactions for in situ and ex situ bioremediation of organic and/or inorganic contaminants.  Dr. Finneran has published 35 peer-reviewed publications, 1 book chapter, and his group has presented its research hundreds of times at national and international symposia. 

He serves on the scientific advisory board of the AEHS/UMASS annual contaminated soils conference, and has been an academic board member of the Battelle Chlorinated Solvents and Site Remediation Conference.  In addition, Dr. Finneran was awarded a National Academy of Sciences (NAS) Kavli Fellow in 2012, which recognizes young researchers considered leaders in the field.

Engineering design services performed by the associated entity, Tersus Environmental of NC, PLLC. (NC License: P-1381)